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Reefs in the Anthropocene – Zombie Ecology?

By Andrew C. Revkin July 14, 2012 12:46 pmJuly 14, 2012 12:46 pm

The Op-Ed section has published “A World Without Coral Reefs,” a provocative and disturbing essay by Roger Bradbury, an ecologist studying resource management at Australian National University. He asserts that these dynamic biological communities, long heralded as the rain forests of the sea, are doomed “zombie ecosystems” — with the triple whammy of overfishing, pollution and ocean acidification from the global buildup of carbon dioxide bound to overwhelm conservationists’ efforts.

John Bruno, a marine ecologist at the University of North Carolina at Chapel Hill and co-creator of the “Sea Monster” blog, said the piece does not reflect the science on reef conditions and threats and fundamentally disagreed with the author’s views on conservation options. Below you can read missives from Olson and Bruno, with a coda laying out my views.

But first here’s a snapshot of coral reef conditions in Belize from 2010, when I traveled there with Pace University students to make a film on efforts to farm shrimp with the environment (including the reefs) in mind:

Read on for the discussion of the zombie reef thesis:

Randy Olson, who described the article as a “huge blow for the truth” in an e-mail message this morning, said (I added links for context):

It’s about “finished baselines.” For a decade Jeremy Jackson and others have been pointing out the problem of “shifting baselines” for coral reefs — looking at today’s degraded ecosystems and not realizing what they once were (the baselines). Bradbury is saying it’s time to stop pointing out “what we’ve lost” and move on to just, “we’ve lost” for coral reefs.

The key social point he is addressing is the struggle that’s emerged for environmental groups between “hope versus truth.” What do you do when the patient’s heart is no longer beating? Do you keep saying, “Sometimes people come back from the dead?” Do you end up like Monty Python’s Black Knight, missing all his limbs but still pretending there’s a serious fight? I don’t know. It’s very sad.

But I do know that I value the truth more than anything else, and when environmental groups get so caught up in their motivational efforts that they’ve lost track of the truth, that is when the door is open for serious disaster. It’s as bad as war correspondents who embed themselves with the troops and lose all perspective.

When I sent the piece to John Bruno this morning, he offered this reaction:

It is scary, but is it true? I don’t think so. I have been called a pathological optimist, but on the other hand, I’ve watched reefs change radically from the dangerous wild places I experienced as a kid in the Florida Keys, to simplified systems with few corals and fewer predators. And this is in just 30 years.

One aspect of my research is focused on documenting and understudying the degradation of coral reef ecosystems, mainly in terms of the loss of reef-building corals. [Click here for an example.] The story is more grim in the Caribbean, where there has been a decline of at least 50 percent (and probably more than 75 percent) of coral populations.

But the picture of coral loss is roughly the same globally. More recently, we’ve been working on the extent of overfishing and predator loss on Caribbean reefs. A healthy unfished reef is inhabited by top predators like sharks and grouper and total fish biomass is roughly 500 grams per square meter. Yet, the average reef has only 20 grams per square meter — obviously an extreme decrease in fish biomass.

So that aspect of Rogers Bradbury’s Op-Ed in today’s New York Times is generally accurate. The world’s coral reefs have indeed changed, are under enormous pressure, and their future is threatened.

But are they really “on a trajectory to collapse within a human generation”? No.

Is there really “no hope of saving the global coral reef ecosystem”? No, there is hope.

And is the “scientific evidence for this is compelling and unequivocal”? No, not remotely.

I think these are valid opinions, but they are not science, nor are they supported by science. What does the science say? It is a complicated picture and there isn’t any way to scientifically test the idea that “reefs are doomed.” Like everything else in conservation (and life) it depends. It depends on when greenhouse gas emissions are reduced and eventually halted. It depends on how big the human populations gets. It depends on when we start managing coral reef fisheries with a modicum of intelligence.

If we increase the atmospheric concentration of CO2 to 2000 parts per million, yeah, I’d agree reefs will probably be toast. [The level is approaching 400 parts per million now.] But I am pretty sure they will persist – albeit in a much diminshed state — if we halted the increase in pressures today.

And what about those pressures? Are they really “accelerating”? No. There is no evidence that the rates of overfishing, ocean acidification and pollution are “accelerating.” I am doubtful that overfishing and pollution are even increasing. (For one, there isn’t a lot left to overfish.) Temperature and acidification are increasing and these pressures do have great inertia, but they are certainly NOT “unstoppable and irreversible”.

We have many examples of places where local threats like fishing and pollution have been reduced or reversed and in some cases like the Florida Keys National Marine Sanctuary, with great success. We also have some — though not many — reefs even in the Caribbean that have a lot of healthy coral and are patrolled by sharks, grouper, snapper, barracuda, and other large carnivores.

The challenge for my generation of scientists is to increase the number of these “quasi-pristine” coral reefs (I’d like to see a tenfold increase) and to halt the decline of the other 90 percent of the world’s reefs. Are this optimistic goals? Sure. But the science suggests this is doable and I’m far from ready to give up on reefs.

As for me, I’ve seen the degradation in many places — most vividly in French Polynesia, where I spent time after college (in 1978) living in a tiny village on the island of Raiatea. [A narrated slide show describes how this trip led me to journalism.] I spent every spare moment snorkeling around coral heads that were dizzylingly dynamic. No matter how close I pressed my mask to some feature, new levels of complexity were revealed. I returned in 1988 and all was changed. While the coral structures were intact, the system was clearly up-ended, with far fewer large fish and weed intruding in many places. (Just as a sidenote, Bruno, who has studied the “turf war” between coral and seaweed, has told me that research shows weedy reefs can be as biologically diverse as coral reefs.)

But like Bruno, I see a lot of evidence for resilience in these systems, if given a chance. Pollution of coastal zones can be cut. Marine protected areas, although the picture is complicated, have the potential to serve as nurseries sustaining fisheries for nearby communities dependent on ocean resources.

In an exchange with Olson this morning, I discussed an element I think is missing from the Bradbury piece. What is being lost is reef systems that humans long exploited and valued as a source of everything from food to building material and — most recently — aesthetic and experiential pleasure (as in the video above). That’s the source of the sense of loss, and, in some people, despair.

But it’s clear to me that corals as a group of living things will almost assuredly* construct glorious reefs in millenniums to come of unimaginable richness.

It would be nice to think that our successors will be around to witness that resurgence, perhaps because our species has overcome its tendency to experience, but not notice or respond to, such “slow drip” losses, hiding in plain sight.

Going forward, on coral conservation and other matters bundled as sustainability, the challenge humans face, to me, is summed up well in the “Serenity Prayer”: to have the serenity to accept the things you cannot change, the courage to change the things you can, and the wisdom to know the difference.

I can’t remember who dragged me to see the movie “Jurassic Park,” but one resonant line in that movie was worth the price of admission, this unforgettable sentence: “Life finds a way.” It popped out at me because it so economically summed up a truth behind all of nature’s stunning diversity and the continuity of the living adventure of Life on Earth.

Yes, things die, lineages go extinct, and coral reefs are in a world of hurt. All true. Also true is there exist heat-tolerant corals, corals that are regularly exposed to (and routinely survive) the extreme stress of finding themselves out in the tropical air at low tide, and many ocean organisms that live through large swings in pH through tidal cycles.

Yes many coral reefs are degraded. Yes it doesn’t look good. But sometimes living diversity supplies marginal adaptations that suddenly fit perfectly into new conditions. Someone (not Darwin) called it “survival of the fittest.” That’s what the phrase means; not survival of the strongest but of the ones who find themselves in the right place at the right time as conditions change to suddenly suit them. Look around; it works.

Agreed, it is past due to raise the alarm that coral reefs in many areas have largely collapsed, and that their future looks bleak. As an anguished lover of reefs and living things generally, and as an ecologist by profession, I cannot picture what it will take for coral reef systems to survive and thrive. But I also cannot picture a world in which no reef corals adapt, persist, and flourish, simply because it’s true: Life finds a way.

Bradbury seems to suggest giving up and spending money on ways to replace the values (for example, fish) that coral reefs have provided. But what would giving up look like? Overfishing is old news, and plenty of people are, in fact, spending money trying to raise fish. Some are making money. Overpopulation: also old news and crucial to everything from water supplies to prospects for peace. One doesn’t need to certify future coral reef destruction to realize that overpopulation is bad for human health and dignity, not to mention a catastrophe for wild living systems. These problems have caused the losses to date and they continue. Warming and acidification are also building.

But to accept that reefs are doomed implies that the best response is to give up hope, thus give up effort. That means we give up on curbing overfishing and allowing rebuilding (yet these two goals are in fact are increasingly working in many places, specifically because people have not given up, and because letting fish recover can work). It means we give up on controlling pollution (in the U.S., the Clean Water Act brought great improvement to rivers so polluted that they actually caught fire multiple times; developing nations deserve to do no less for themselves). It means we give up on population, whose most effective solving strategy is to teach girls to read and write.

Giving up, while reefs still flourish in many places, means accepting what is unacceptable, and abandoning work on situations that can likely be improved. It means deciding to be hopeless. It means giving up on the reefs, the fishes, and the people, who need all the combined efforts of those who both know the science best—and who, while life exists, won’t give up.

The science is clear that reefs are in many places degraded and in serious trouble. But no science has, or likely can, determine that reefs and all their associated non-coral creatures are unequivocally, equally and everywhere, completely doomed to total non-existence. In fact, much science suggests they will persist in some lesser form. Bleak prospects have been part of many dramatic turnarounds, and, who knows, life may, as usual—with our best efforts—find a way.

[July 15, 12:12 p.m. | Updated |There was a logical inconsistency in the way I initially wrote this sentence. Adjusted.]

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By 2050 or so, the human population is expected to pass nine billion. Those billions will be seeking food, water and other resources on a planet where humans are already shaping climate and the web of life. Dot Earth was created by Andrew Revkin in October 2007 -- in part with support from a John Simon Guggenheim Fellowship -- to explore ways to balance human needs and the planet's limits.